Just how reliable is the MMU2
There are numerous posts on this forum about users who have had a variety of problems with the MMU2. What I cant get a feel for is what percentage of users experience problems because happy users don't post as much and a lot of negative posts on a forum like this dont necessarily give the whole picture.
The concept of the MMU2 appeals to me but I would like some HONEST feedback about how well this works and how likely it would be to have major problems.
I understand that a system as complex as this will be more complicated to set up and calibrate. I would also like to know whether problems are more likely with particular versions of the base machine
Peter
RE: Just how reliable is the MMU2
Maybe search around instead of adding yet another "who's got it working?" thread?
RE: Just how reliable is the MMU2
@vintagepc
I am sorry but smart-arse replies don't impress me at all. I think that offering help and advice, particularly to new users, is what forums should be about. I did "search around" and I must admit that I didn't find the post you linked to.
Thanks for that but I am still looking for some constructive comments.
RE: Just how reliable is the MMU2
As far as I'm concerned I'm happy with my MMU2. Following the build-instructions from the manual my MMU2 printed the shorter demo-prints (sheep, lizard) right out of the box, but I wouldn't recommend it to most people.
The Mk3 is something I'd almost call "consumer-friendly". But the MMU2 adds a lot more places where things can go wrong. I don't think it has any serious flaw, but it's just more complex - and makes trouble-shooting more difficult.
I'd say: expect some problems.
- The setup with the buffer maybe has to be adjusted to fit to the workplace. For a continuous printing-operation the buffer is probably best, but for experimenting and trouble-shooting it is clumsy.
- Some mods are advisable - I think pneumatic fittings on the MMU should be standard.
- There are a lot of places in the filament path where filament can get stuck - I think my prints hung on each one of them at least once - but so far the problem was never serious enough for me to replace parts with mods that have more friendly chamfered channels. But in case Prusa publishes an official new version with nicer channels I'll be happy to upgrade.
RE: Just how reliable is the MMU2
@andreas-d10
Thank you - thats really helpful
RE: Just how reliable is the MMU2
@drpeej
Most of the posts here in the forum are honest. Nobody is trying to sell you something as we are not related to PR. There are only a handful of people here who are PR employees.
So far I've seen people using their MMU2 for various things and are very happy about current state (firmware and hardware got much better and there are still improvements in the pipeline). But there are also people who gave up and dismantling MMU2. We don't have any statistics about the success rate. So it's hard to tell how likely you will belong to the one or the other group.
I was one of the early adopters of the MMU2 (on MK3) and I don't regret the buy. My house is already full of multi color prints and I still prefer the design over Palette. The success rate of the prints is near 100% although some interventions are still here and there. But it gives me the option to use any filament and any combination of filaments. Also in case any issues occur, I can fix it and continue with a print.
So at the end it's up to you if you want to go on the MMU journey. Doesn't matter which product you pick, expect more complexity and more things to look for.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: Just how reliable is the MMU2
@nikolai-r
Thank you - very helpful. Sorry to be dim but what is Palette? I have seen several references to it but I dont know what it is
RE: Just how reliable is the MMU2
Ignore that - I've found it!
RE: Just how reliable is the MMU2
@drpeej
I have much the opposite experience as @nikolai-r. Not only I have I yet to get a single multi-color print to work in the many months that I have had the MMU2S, it has also caused the printer to fail at about a 90% rate during single color prints.
I know it is capable of amazing prints, I've seen them; but don't expect that its just going to work for you, it seems to be pretty hit or miss.
RE: Just how reliable is the MMU2
It's nowhere near the same level as the base Mk3. It's probably closer to where printers were 3-4 years ago. The Mk3 just works. Adjustments are easy, error messages are clear.
The MMU2s has a lot more trial and error on things that are fairly critical - spring tension and IR sensor adjustment have been my nemeses. When things go wrong you get the dreaded "MMU needs user attention". At that point it's up to you to try to solve things through button presses that are like setting an old digital watch. Even then, the firmware sometimes gets really confused and will do dumb things that need you to reset the printer and start over. Or the worst part, when the MMU is feeling uncooperative and you can't even get single color prints done.
That being said, just as it was possible to do 3d printing 3 years ago, it's possible to get successful MMU prints today. Expect a lot of adjustments and failures getting to that point.
RE: Just how reliable is the MMU2
I just finished assembling the MMU2S unit a couple of days ago. So far I am rather disappointed of the result and the reliability of the whole assembly. I didn't succeed yet to finish a single print.
I am realising that it's not a product suited for everyone. Here are few comments.
- The buffer is rather messy to use. It's ok if you seldomly change rolls, but if you change rolls at every print it's a pain.
- The fw is plagued with bugs. While the Merlin-derived firmware of the printer is stable, the MMU unit is rather immature. The PINDA sensor get stuck to 1 after few minutes of printing, making filament change almost impossible.
- I do my printing with exotic material most of the time (Nylon, Carbon Fiber, ...) and the unit is quite sensitive to the friction levels in the PTFE tubes, i.e. it's almost impossible to print with Carbon Fiber. In any case it's problematic even with off the shelf good quality PLA
I will try printing for another few days and then decide if I will retire prematurely the unit
RE: Just how reliable is the MMU2
- The buffer is rather messy to use. It's ok if you seldomly change rolls, but if you change rolls at every print it's a pain.
While nowhere near a perfect solution this: https://www.thingiverse.com/thing:3545935 greatly reduces the pain in feeding filament into the buffer.
- The PINDA sensor get stuck to 1 after few minutes of printing, making filament change almost impossible.
Do you mean the FINDA sensor? (The one on the MMU?) If so, there are multiple versions of the selector that have a magnet in it (using one of the extras that came with the kit) to alleviate this problem. See: https://www.thingiverse.com/thing:3528314
- I do my printing with exotic material most of the time (Nylon, Carbon Fiber, ...) and the unit is quite sensitive to the friction levels in the PTFE tubes, i.e. it's almost impossible to print with Carbon Fiber. In any case it's problematic even with off the shelf good quality PLA
I would recommend something like: https://www.thingiverse.com/thing:3233579 to remove one major pinch point (and make it a lot easier to disconnect/troubleshoot) and if you are still having issues maybe try something like https://www.amazon.com/dp/B079P92HN9 .
I still don't have my MMU2 working, but its getting closer with each user mod.
RE: Just how reliable is the MMU2
Hello and thanks for your answer.
The mods are very interesting, especially https://www.thingiverse.com/thing:3545935 that is answering a specific immediate pain point.
I notice that the IR sensor on the extruder is giving me problems as well. If you have a mod for this too it would be great.
Do you mean the FINDA sensor? (The one on the MMU?) If so, there are multiple versions of the selector that have a magnet in it (using one of the extras that came with the kit) to alleviate this problem. See: https://www.thingiverse.com/thing:3528314
Yes. I meant the FINDA sensor.
It get stuck for good, even if I extract it from the MMU unit and place it far from any metal object it reads still 1. The only solution to get it back to work is to switch off and switch on the printer.
I believe it's either a faulty sensor or a firmware bug. It's not related to anything mechanical.
RE: Just how reliable is the MMU2
Quick question! Did anyone try to lubricate the PTFE tubes with dry PTFE lubricant?
I was thinking about something similar ti this: https://www.amazon.es/WD-40-Specialist-34382-Lubricante-seco/dp/B01N56KYXE/
RE: Just how reliable is the MMU2
@luca-vicini
Be very careful about using slick PTFE tubes or lubricating them because you can make the problem worse (the filament can slide out backwards from the MMU for example).
RE: Just how reliable is the MMU2
Quick question! Did anyone try to lubricate the PTFE tubes with dry PTFE lubricant?
I was thinking about something similar ti this: https://www.amazon.es/WD-40-Specialist-34382-Lubricante-seco/dp/B01N56KYXE/
that could potentially ruin your prints because it will stick to the filament and ruin your layer adhesion.
there should be no need for something like this.
RE: Just how reliable is the MMU2
that could potentially ruin your prints because it will stick to the filament and ruin your layer adhesion.
there should be no need for something like this.
As with everything YMMV but I used 3 in 1 oil in my PTFE tubes for over a year to reduce friction and never had any issues with the oil sticking to the filament or with layer adhesion. This is a pretty common solution to reduce friction in PTFE tubes, especially in Bowden style printers. Just don't over do it (a couple drops will do).
That being said, if you have the money and want to reduce friction in the PTFE tubes, you can buy "slick" PTFE tubes that don't require you to lubricate them.